HIV/AIDS is a major contributor to morbidity and mortality in Uganda. Despite aggressive advances in HIV prevention efforts, recent data suggest that HIV prevalence is increasing generally, and HIV knowledge, a direct contributor to behavior, is on the decline among young people specifically as compared to a decade ago. The Internet is a promising mode of intervention delivery in resource poor-settings because the costs associated with scaling up are minimal;dissemination online is the same if one person or 100,000 people use the program. Just as important, it provides access to important health information in a stigma-free, anonymous atmosphere. Our recent data indicate that 45% of adolescents in Mbarara, Uganda have used the Internet, 78% of whom went online at least once in the previous week. Eighty-one percent of respondents in the same survey indicated they would go to an HIV prevention web site if it existed. Based upon these data, we propose to develop a culturally appropriate, Internet-based HIV prevention program designed specifically for Ugandan adolescents between the ages of 12 and 18 years. Our specific aims are as follows: Specific Aim 1: Design a 6-hour, Internet-based HIV prevention program for adolescents. Content will be culturally tailored to the HIV preventive information, motivation, and behavioral skills needs of Ugandan adolescents. Specific Aim 2: Test the intervention in a randomized controlled trial (n=500) among adolescents attending grades Secondary 1-4 (similar to US high school grades 8th -11th) at day schools in Mbarara. Our main outcome measure is the frequency of unprotected sex 6-months post-intervention. The secondary outcome will be sexual abstinence 6-months post-intervention. We determine intervention efficacy by testing for a significant difference in outcomes between intervention and control group in an intent-to-treat analysis. This project has the potential to develop low-cost and scalable interventions to HIV transmission risk behaviors among adolescents in Uganda.